Preheat the oven to 300°F / 175ºC, and coat an 8”-square pan with nonstick cooking spray, and line with parchment paper.
In a large bowl, stir together the peanut butter and cashew milk. Stir in the salt, vanilla, stevia, and maple syrup. Pour in the oat flour, and sprinkle the baking powder over the oat flour (to prevent it from clumping!).
Stir in the oat flour and baking powder until just incorporated. Stir in miniature chocolate chips.
Spread the mixture into the prepared pan. Bake at 300°F for 12-15 minutes. Cool completely to room temperature in the pan, and let the bars rest for at least 6 hours once at room temperature for the best taste and texture before slicing and serving.